Sour Grapes inhabit Grape Grove and a few other places in Tuberia; they appear harmless, and are hanging from the ceiling (or floating up to it), but whenever they detect movement, they scream and fall to earth, hoping to squash and consume any hapless prey that is beneath. They are tough and bouncy, being able to survive huge drops, and contain a ballast gas they can use to float after they have landed. They cannot be killed.